1 /* 2 * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "jvm.h" 27 #include "logging/log.hpp" 28 #include "memory/allocation.inline.hpp" 29 #include "runtime/arguments.hpp" 30 #include "runtime/java.hpp" 31 #include "runtime/mutex.hpp" 32 #include "runtime/mutexLocker.hpp" 33 #include "runtime/orderAccess.hpp" 34 #include "runtime/os.hpp" 35 #include "runtime/perfData.hpp" 36 #include "runtime/perfMemory.hpp" 37 #include "runtime/safepoint.hpp" 38 #include "runtime/statSampler.hpp" 39 #include "utilities/align.hpp" 40 #include "utilities/globalDefinitions.hpp" 41 42 // Prefix of performance data file. 43 const char PERFDATA_NAME[] = "hsperfdata"; 44 45 // Add 1 for the '_' character between PERFDATA_NAME and pid. The '\0' terminating 46 // character will be included in the sizeof(PERFDATA_NAME) operation. 47 static const size_t PERFDATA_FILENAME_LEN = sizeof(PERFDATA_NAME) + 48 UINT_CHARS + 1; 49 50 char* PerfMemory::_start = NULL; 51 char* PerfMemory::_end = NULL; 52 char* PerfMemory::_top = NULL; 53 size_t PerfMemory::_capacity = 0; 54 int PerfMemory::_initialized = false; 55 PerfDataPrologue* PerfMemory::_prologue = NULL; 56 bool PerfMemory::_destroyed = false; 57 58 void perfMemory_init() { 59 60 if (!UsePerfData) return; 61 62 PerfMemory::initialize(); 63 } 64 65 void perfMemory_exit() { 66 67 if (!UsePerfData) return; 68 if (!PerfMemory::is_usable()) return; 69 70 // Only destroy PerfData objects if we're at a safepoint and the 71 // StatSampler is not active. Otherwise, we risk removing PerfData 72 // objects that are currently being used by running JavaThreads 73 // or the StatSampler. This method is invoked while we are not at 74 // a safepoint during a VM abort so leaving the PerfData objects 75 // around may also help diagnose the failure. In rare cases, 76 // PerfData objects are used in parallel with a safepoint. See 77 // the work around in PerfDataManager::destroy(). 78 // 79 if (SafepointSynchronize::is_at_safepoint() && !StatSampler::is_active()) { 80 PerfDataManager::destroy(); 81 } 82 83 // Remove the persistent external resources, if any. This method 84 // does not unmap or invalidate any virtual memory allocated during 85 // initialization. 86 // 87 PerfMemory::destroy(); 88 } 89 90 void PerfMemory::initialize() { 91 92 if (is_initialized()) 93 // initialization already performed 94 return; 95 96 size_t capacity = align_up(PerfDataMemorySize, 97 os::vm_allocation_granularity()); 98 99 log_debug(perf, memops)("PerfDataMemorySize = " SIZE_FORMAT "," 100 " os::vm_allocation_granularity = %d," 101 " adjusted size = " SIZE_FORMAT, 102 PerfDataMemorySize, 103 os::vm_allocation_granularity(), 104 capacity); 105 106 // allocate PerfData memory region 107 create_memory_region(capacity); 108 109 if (_start == NULL) { 110 111 // the PerfMemory region could not be created as desired. Rather 112 // than terminating the JVM, we revert to creating the instrumentation 113 // on the C heap. When running in this mode, external monitoring 114 // clients cannot attach to and monitor this JVM. 115 // 116 // the warning is issued only in debug mode in order to avoid 117 // additional output to the stdout or stderr output streams. 118 // 119 if (PrintMiscellaneous && Verbose) { 120 warning("Could not create PerfData Memory region, reverting to malloc"); 121 } 122 123 _prologue = NEW_C_HEAP_OBJ(PerfDataPrologue, mtInternal); 124 } 125 else { 126 127 // the PerfMemory region was created as expected. 128 129 log_debug(perf, memops)("PerfMemory created: address = " INTPTR_FORMAT "," 130 " size = " SIZE_FORMAT, 131 p2i(_start), 132 _capacity); 133 134 _prologue = (PerfDataPrologue *)_start; 135 _end = _start + _capacity; 136 _top = _start + sizeof(PerfDataPrologue); 137 } 138 139 assert(_prologue != NULL, "prologue pointer must be initialized"); 140 141 #ifdef VM_LITTLE_ENDIAN 142 _prologue->magic = (jint)0xc0c0feca; 143 _prologue->byte_order = PERFDATA_LITTLE_ENDIAN; 144 #else 145 _prologue->magic = (jint)0xcafec0c0; 146 _prologue->byte_order = PERFDATA_BIG_ENDIAN; 147 #endif 148 149 _prologue->major_version = PERFDATA_MAJOR_VERSION; 150 _prologue->minor_version = PERFDATA_MINOR_VERSION; 151 _prologue->accessible = 0; 152 153 _prologue->entry_offset = sizeof(PerfDataPrologue); 154 _prologue->num_entries = 0; 155 _prologue->used = 0; 156 _prologue->overflow = 0; 157 _prologue->mod_time_stamp = 0; 158 159 OrderAccess::release_store(&_initialized, 1); 160 } 161 162 void PerfMemory::destroy() { 163 164 if (!is_usable()) return; 165 166 if (_start != NULL && _prologue->overflow != 0) { 167 168 // This state indicates that the contiguous memory region exists and 169 // that it wasn't large enough to hold all the counters. In this case, 170 // we output a warning message to the user on exit if the -XX:+Verbose 171 // flag is set (a debug only flag). External monitoring tools can detect 172 // this condition by monitoring the _prologue->overflow word. 173 // 174 // There are two tunables that can help resolve this issue: 175 // - increase the size of the PerfMemory with -XX:PerfDataMemorySize=<n> 176 // - decrease the maximum string constant length with 177 // -XX:PerfMaxStringConstLength=<n> 178 // 179 if (PrintMiscellaneous && Verbose) { 180 warning("PerfMemory Overflow Occurred.\n" 181 "\tCapacity = " SIZE_FORMAT " bytes" 182 " Used = " SIZE_FORMAT " bytes" 183 " Overflow = " INT32_FORMAT " bytes" 184 "\n\tUse -XX:PerfDataMemorySize=<size> to specify larger size.", 185 PerfMemory::capacity(), 186 PerfMemory::used(), 187 _prologue->overflow); 188 } 189 } 190 191 if (_start != NULL) { 192 193 // this state indicates that the contiguous memory region was successfully 194 // and that persistent resources may need to be cleaned up. This is 195 // expected to be the typical condition. 196 // 197 delete_memory_region(); 198 } 199 200 _destroyed = true; 201 } 202 203 // allocate an aligned block of memory from the PerfData memory 204 // region. This method assumes that the PerfData memory region 205 // was aligned on a double word boundary when created. 206 // 207 char* PerfMemory::alloc(size_t size) { 208 209 if (!UsePerfData) return NULL; 210 211 MutexLocker ml(PerfDataMemAlloc_lock); 212 213 assert(is_usable(), "called before init or after destroy"); 214 215 // check that there is enough memory for this request 216 if ((_top + size) >= _end) { 217 218 _prologue->overflow += (jint)size; 219 220 return NULL; 221 } 222 223 char* result = _top; 224 225 _top += size; 226 227 assert(contains(result), "PerfData memory pointer out of range"); 228 229 _prologue->used = (jint)used(); 230 _prologue->num_entries = _prologue->num_entries + 1; 231 232 return result; 233 } 234 235 void PerfMemory::mark_updated() { 236 if (!UsePerfData) return; 237 238 assert(is_usable(), "called before init or after destroy"); 239 240 _prologue->mod_time_stamp = os::elapsed_counter(); 241 } 242 243 // Returns the complete path including the file name of performance data file. 244 // Caller is expected to release the allocated memory. 245 char* PerfMemory::get_perfdata_file_path() { 246 char* dest_file = NULL; 247 248 if (PerfDataSaveFile != NULL) { 249 // dest_file_name stores the validated file name if file_name 250 // contains %p which will be replaced by pid. 251 dest_file = NEW_C_HEAP_ARRAY(char, JVM_MAXPATHLEN, mtInternal); 252 if(!Arguments::copy_expand_pid(PerfDataSaveFile, strlen(PerfDataSaveFile), 253 dest_file, JVM_MAXPATHLEN)) { 254 FREE_C_HEAP_ARRAY(char, dest_file); 255 if (PrintMiscellaneous && Verbose) { 256 warning("Invalid performance data file path name specified, "\ 257 "fall back to a default name"); 258 } 259 } else { 260 return dest_file; 261 } 262 } 263 // create the name of the file for retaining the instrumentation memory. 264 dest_file = NEW_C_HEAP_ARRAY(char, PERFDATA_FILENAME_LEN, mtInternal); 265 jio_snprintf(dest_file, PERFDATA_FILENAME_LEN, 266 "%s_%d", PERFDATA_NAME, os::current_process_id()); 267 268 return dest_file; 269 } 270 271 bool PerfMemory::is_initialized() { 272 return OrderAccess::load_acquire(&_initialized) != 0; 273 }